TABLE 2.

Significantly higher abundance of Bacteroidetes and lower abundance of Actinobacteria and Firmicutes among African-Americans

Taxon	Among all participants (n = 1,616)				Genetic African ancestry percentage (n = 882)
	% relative abundance		Coefficienta	P valueb	Coefficienta	P valuea
	European- Americans	African- Americans
Phylum Bacteroidetes
Family Porphyromonadaceae	0.19	0.67	0.38	0.03	0.88	4.81 × 10−6
Genus Porphyromonas	0.18	0.64	0.37	0.05	0.85	1.91 × 10−5
Species Prevotella denticola	0.04	0.11	0.49	1.56 × 10−3	0.87	1.22 × 10−5
Phylum Actinobacteria	11.05	10.09	−0.38	6.14 × 10−8	−0.46	2.78 × 10−6
Family Micrococcaceae	5.77	5.47	−0.41	1.81 × 10−6	−0.39	8.65 × 10−4
Genus Rothia	5.77	5.47	−0.42	1.14 × 10−6	−0.39	1.04 × 10−3
Species Rothia mucilaginosa	4.80	4.65	−0.41	1.21 × 10−5	−0.35	5.91 × 10−3
Phylum Firmicutes
Family Carnobacteriaceae	1.35	1.13	−0.22	0.03	−0.26	0.02
Genus Granulicatella	1.32	1.09	−0.24	0.02	−0.25	0.03
Species Granulicatella adiacens	1.28	1.04	−0.23	0.03	−0.25	0.03
Species Streptococcus oligofermentans	0.46	0.22	−0.42	7.88 × 10−5	−0.48	8.50 × 10−4
Species Streptococcus sp. oral taxon 057	9.89	8.85	−0.17	0.03	−0.29	2.77 × 10−4
Family Peptostreptococcaceae	0.09	0.20	0.41	2.35 × 10−4	0.66	5.48 × 10−6

^aFor each sample, centered log-ratio transformation was used to normalize taxon read counts. The associations of taxon abundance with race/African ancestry percentage were evaluated using linear regression analyses.

^bBonferroni-corrected P values, adjusted for 25 independent tests.